Relief valve



w. ERNST 2,323,021

RELIEF VALVE Julie 29, 1943,

Original Filed July 26; 1941 Patented June 29, 1943 UNITED si'n'rrzs ,PAT|51-1'|" OFFICE RELIEF VALVE Walter Ernst, Monntfiilead, Ohio, assignor to The Hydraulic Development Corporation, Inc., Wilmington, DeL, a corporation oi Delaware Original application July 26, 1941-, Serial-No.

Divided and this application October 20, 1941, Serial No. 415,697

G Claims. (01. 137-53) This invention relates to valves and, more particularly, to improvements in relief valves which,

in response'to, a predetermined pressure acting thereupon, release an outlet opening to relieve pressure therethrough.

Most of therelief valves heretofore known have the drawback that, when using high pressure and correspondingly strong control springs,

the valve member vibrates violently and frequently causes breakage of delicate gauges connected Structural arrangement Refe'rringnow to the drawing in detail, Figure 1 diagrammatically illustrates a hydraulic press circuit in connection with a relief valve ing to the invention.

' The hydraulic circuit of Figure 1 comprises a main'cyiinder i having reciprocably mountedm therein a double-acting pistonconnected by thereto. Moreover, these known devices make it impossible to stabilize the'desired pressure.

In my copending application, Serial No.

404,219, flied July 26, "1941, oi which the present application is a division, there is disclosed a reliei valve which overcomes the above mentioned drawback by admitting fluid pressure into the chamber housing the control spring.

It is an object of the present invention to further improve the valve structure disclosed in my said copending application No. 404,219 so as to enable a lighter construction thereof.

It is a further object to provide a spring controlled pressure relieivalve with a differential valve member, in which the thrust of the spring is aided by fluid pressure acting on said 'diiierential valve member.

These and other objects and advantages of the invention will appear more clearly in the following specification in connection with the accompanying drawing, in which:

Figure 1 diagrammatically illustrates 'a hydraulic press circuit in connection vaivegas shownin Figure 2.

Figure 2 shows an embodiment of the invention with a passageway interconnecting the spring chamber and the area upon which acts the pressure to be controlled.

General arrangement In general, the valve according to the invention comprises a spring chamber which houses the control springior opposing the movement of the valve member.

' According to an embodiment of the invention,

the spring chamber continuously communicates through a passage in the valve member withan area on the valve member continuously acted upon by the pressure to be controlled. The pres- .sure'in the valve chamber acts somewhat like a shock absorber or stabilizer, thereby enabling a smooth opening of the valve and a stabilization oi the v alve member in its releasing position when a predetermined pressure has acted upon the said area. 1

a ram 3 with a platen 4, whichin itsturn comprises clamping cylinders 5. Reciprocably mounted in the clamping cylinders 5 are clamping plungers 6 connected t'o'a clamping platen I.

The clamping cylinders 5 communicate with conduits I and 9 interconnected with each other and leading to the inlet opening ill of the pressure relief valve ii. i l

The valve ii as shown in Figures 1 and 2 communicates through conduits i2 and 35 with the inlet port of an adjustable choke or throttle ll,

which in its turn communicates with a conduit I5 leading to a fluid reservoir or surge tank It.

The tank It is connected with the suction line with a relief 1 t is a valve'member 2 1 with a longitudinal bore 2| ll of a fluid pump i8 of any desired type, the

'pressure'side of which communicates witha fourway'valve is through a conduit 20. The valve ll" has a fluid connection 2! to the tank ii, a fluid connection to theup'per portion of the main cylinder i, and a fluid connection 23 to the lowe portion oi the main cylinder l.

The relief valve II is set for a desired pressure in the clamping cylinders i and, when the clamping platen l at the downward stroke of l the ram 3 {engages the work piece and thereby .,comes,to ahalt, while the ram 3 continues its downward movement, pressure builds up in the clamping cylinders 5 which, at theattainment or a predetermined value determined by the setting I of the relief valve, causes the latter to open. The

clamping pressure in the clamping cylinders I may be observed on the gauge 24.

, The pressure relief valve shown in Figures 1 and 2 comprises a casing 25 with the inlet opening Ill adapted to be connected to the pressure line B and leading to the cylinder bore 28 inthe valve casing 25.

Reciprocably mounted in the cylinder bore 26 therethrough, which latter continuously connects the inlet opening i0 with a spring casin or spring chamber 28 arranged on top of the valve casing 25. The spring casing 29. houses a spring 30, the

. lower end of which rests upon a disc 3i i which is supported by the valve member 21 and may be connected thereto in any convenient manner.

The upper end of spring 30 is engaged by a disc 3! held in its position by an adjustable screw 32. By adjusting the screw 32, the pressure of the spring 30 may be varied in accordance with the desired setting of the valve.

The valve casing 25 comprises an annular passageway 33 surrounding the valve member 21 and communicating .with an outlet port 34 which is connected with the conduit l2. Branching off from the conduit I2 is a conduit 35 leading to a differential chamber 36 in the casing 25 for conveying fluid pressure from the conduit. I2 to the diflerential piston area 31.

Operation or closing position for opening or closing said outlet port, said valve member having a first area adjacent saidinlet port and an opposed smaller area and also being provided with an extension extending into a spring chamber, spring means provided in said chamber and acting upon said extension for continuously urging said valve member into closing position, conduit means con tinuously efiecting fluid connection between said inlet port and said extension for aiding said spring means in urging said valve member into its closing position, and means responsive to a predetermined pressure on said first area for supplying pressure fluid from said first area to said smaller area.

3. In combination in a valve, a valve casing having an inlet port for connection with a pressure line and an outlet port for connection with an exhaust line, a valve member reciprocable in said casing and movable selectively into opening or closing position for opening or closing said outlet port, said valve member having a first area adjacent said inlet port and an opposed smaller area, spring means arranged in a spring chamber and acting upon an extension of said valve member for continuously urging said valve member builds up in conduit l2 and is conveyed through conduit 35 into the differential chamber 36 where it acts upon the differential area 31. This pressure aids the spring. 30, thereby bringing about a stabilization of the valve member 21 so that chattering of the valve member 2'! is prevented and a predetermined pressure maintained in' the clamping cylinders 5.

Due to the passageway 28, pressure is continuously conveyed from the inlet opening Illinto the spring chamber 29. ing in the spring chamber 29 and continuously conveyed thereto from the inlet opening l0 has a stabilizing influence on thevalve member 21, o as o prevent jumping 0f the Valve member at each slight change in the pressure acting upon the main area 46..

It will be understood that I desire to comprehend within my invention such modifications as come within the scope of the claims and the invention. I a

Having thus fully described my'invention .what I claim as new and desire to secure, by Letters Patent is:

1. In combination in a valve, a valve casing having an inlet port adapted to be connected with a pressure line and an outlet port adapted to be connected with an exhaust line,. a valve member reciprocable in said casing. and movable selectively intoopening or closing position for opening or closing said outlet port, said Valve member having a first area adjacent said inlet port and an opposed smaller area and member to said extension to aid said yielding The fluid pressure prevail ciprocably mounted in said chambers and having means in urging said valve member into its closing position.

2. In combination in a valve, a valve casing having an inlet port 'for connection with a pressure line and an outlet port for connection with an exhaust line, a valve member reciprocable in said casing and movable selectively into opening into closing position, conduit means continuously establishing fluid connection between said inlet port and. said extension to convey fluid to the latter for aiding said spring means in urging said valve member into closing position, means responsive to movement of said valve member into opening position for conveying fluid pressure from said first area to said smaller area, and means associated with said last mentioned means for maintaining a predetermined miinmum pressure on said smaller area while said valve member is in its opening position.

4. In combination in a valve, a valve casing having an inlet port for connection with a pressure line and an outlet port for connection with an exhaust line, a valve member reciprocable in said casing and movable selectively into opening or closing position for opening or closing said outlet port, said valve member having a first area adjacent said inlet port and an opposed smaller aiding said spring means in urging said valve member into its closing position, choke means for building up back pressure atsaid outlet port, and

conduit means interposed between said choke means and said outlet port and communicating.

with the latter for conveying pressure from said first area to said smaller area in response to the movement of said valve member into opening position.

5. In combination in a valve, a valve casing having a main chamber and an auxiliary chamber, said main chamber being provided with an inlet and an outlet opening, a valve member rea main area cooperating with said main chamber and an oppositely located auxiliary area cooperating with said auxiliary chamber, said main area being larger than said auxiliary area, a spring chamber connected to said casing, reciprocable means arranged in said chamber and connected to said valve member, spring mean acting upon said reciprocable member for continuously urgsaid outlet opening, conduit means for continuously hydraulically connecting said main chamber with said spring chamber for conveying fluid pressure from said main chamber to said reciprocable means to aid said spring means in urging said valve member into closing position, and means responsive to the release of said outlet opening by said valve member for conveying additional fluid pressurefrom said main chamber to said auxiliary chamber to further aid said spring means in itsten'dency to move said valve member into closing position. I

6. In combination in a valve comprisinga valve casing with a valvebore having an inlet and an outlet opening, a diflerential plunger reciprocably mounted in said bore and having a main area, adapted to be acted upon by pressure fluid admitted through said inlet opening, for moving said plunger into position for releasing said outlet opening, a chamber associated with said casing and housing yielding means for continuously urging said plunger into position for closing said outlet opening; a passageway through said plunger for continuously eifecting hydraulic connection between said inlet Opening and said chamber to convey pressure fluid into said chamher for acting on said plunger in the same direction assaid yielding means, conduit-means connecting said outlet opening with an auxiliary area on said plunger oppositely directed to said main area, said conduit means being adapted in response to the release of said outlet opening to convey. pressure fluid from said inlet opening to saidauxiliary area to aidsaid yielding means in urging said plunger into closing position, and means associated with said conduit means for creating a predetermined back pressure at said outlet opening. v

- WALTER ERNST. 

